No, those files are specific to those packages. Unless any of the footprints were in ".dxf" format it would be possible, however, you would then need to add the attributes and Pin information by hand. The only exception is if there was a footprint for PADS and then you open it with that package, then save a file with it, you could open it in Ultiboard (the file) and add the footprint to your database.
On these cases, you should get ahold of the technical drawings from the manufacturer, and either use the component wizard or create the footprint from scratch using Ultiboard.
Nestor